Install Water Heater on Volvo MD17C

[foolishsailor]

OK first I must out myself as a lover of these old Volvos....

Yea I know the horror stories of cost of parts, etc. but my last two boats both had old Volvos, the one previous had a MD2B and this one has a MD17c. Maybe I have dodged many bullets but these two engines really performed flawlessly for me during my ownership, approx 5 years each...

So my question is - any guidance on the installation of a water heater. I already have the heater itself and have a general idea of the needs to tap into the coolant system. What I would love is if a fellow md17c owner had photos of the install and/or someone has some tips on drilling/taping of the threads in the coolant system to allow the install.

Any experience also on how it affects the engine operating temperature....

Thanks

[Viking Sailor]

I have had a raw water cooled MD17D (slight mod to MD17C) since '78. Tried to connect the hot raw coolant water output from the manifold thru the water heater without success. The water temp is just to low. I ended up using a propane instant water heater.

If you can get it to work I would love to know how you did it.

Best of luck to you,

[Cheechako]

Yeah, it will need to be fresh cooled. Those old MD2B's and the other larger variants were one of the best ever built for sure.

[Pete7]

Okay, so why can't a raw water cooled 3 clyinder volvo be connected to a calorifier? after all the stat opens at 60.c and is fully open at 74.c.

Our volvo 2003 (28hp) is raw water cooled and heats a 20l calorifier in about 40 minutes of motoring. Doesn't do anything at tickover mind because it doesn't produce enough heat, but open the throttle to 2000 revs and lots of hot water available.

The 2003 has a copper pipe which exits the engine and goes to the exhaust elbow. All volvo have done is interupt this pipe so that it goes to the calorifier and then back to the pipe before entering the exhaust elbow. I don't know the MD series engine, but can't the exhaust feed pipe be interupted?

Volvo Penta Exploded view / schematic Water Cooled Exhaust Bend - MarinePartsEurope.com

[Viking Sailor]

Originally Posted by Pete7

Okay, so why can't a raw water cooled 3 clyinder volvo be connected to a calorifier? after all the stat opens at 60.c and is fully open at 74.c.

Our volvo 2003 (28hp) is raw water cooled and heats a 20l calorifier in about 40 minutes of motoring. Doesn't do anything at tickover mind because it doens't produce enough heat, but open the throttle to 2000 revs and lots of hot water available.

The 2003 has a copper pipe which exits the engine and goes to the exhaust elbow. All volvo have done is interupt this pipe so that it goes to the calorifier and then back to the pipe before entering the exhaust elbow. I don't know the MD series engine, but can't the exhaust feed pipe be interupted?

Volvo Penta Exploded view / schematic Water Cooled Exhaust Bend - MarinePartsEurope.com

Yep, that is what I did, and it didn't work. The builder and commissioning crew didn't install the engine heating feature that was available on the water heater. It was as if they already knew that it wouldn't work.

[roverhi]

I had a raw water cooled MD2 with an engine cooled water heater. Would not produce hot water. Deep sixed the heater when it got rusty. My current freshwater cooled Yanmar will produce hotwater in a very short period of time with a similar hot water tank.

[nitpik]

I have a 1981 Volvo MD 17 in my little schooner. Wonderful engine - extremely reliable! It is keel cooled, and has no trouble providing hot water in about 20 minutes. It even heats the water at idle. Didn't realize other owners had problems in this regard. I did not set it up originally, but it appears to be a very straight forward installation.

[Cheechako]

Originally Posted by Pete7

Okay, so why can't a raw water cooled 3 clyinder volvo be connected to a calorifier? after all the stat opens at 60.c and is fully open at 74.c.

Our volvo 2003 (28hp) is raw water cooled and heats a 20l calorifier in about 40 minutes of motoring. Doesn't do anything at tickover mind because it doesn't produce enough heat, but open the throttle to 2000 revs and lots of hot water available.

The 2003 has a copper pipe which exits the engine and goes to the exhaust elbow. All volvo have done is interupt this pipe so that it goes to the calorifier and then back to the pipe before entering the exhaust elbow. I don't know the MD series engine, but can't the exhaust feed pipe be interupted?

Volvo Penta Exploded view / schematic Water Cooled Exhaust Bend - MarinePartsEurope.com

If yours runs hot enough no reason you cant... my experience is most dont run hot enough....

[Dennis.G]

If your diesel is not running hot enough to make hot water, you engine is running much too cool. Restrict cooling water flow and get operating temp higher. Running a diesel cold is death to engine.

[gjordan]

Dennis G , Just remember that if a raw water cooled diesel is run too hot it is a form of slow suicide for the engine. Engine heated hot water only sometimes works with raw water cooled engines._____Grant.

[roverhi]

Because of salt precipitation at temps higher than around 150 degrees, raw water cooled engines must run cold. If you run them above that magic temperature, what ever that temp is, salt precipitates out of the water and forms deposits in the engine that will eventually block water passages and destroy the engine. Fresh water cooled diesels, those with heat exchangers or keel coolers, are run at much higher temperatures up to 212 degrees and some because there is no saltwater in the engine.

[Cheechako]

Originally Posted by Dennis.G

If your diesel is not running hot enough to make hot water, you engine is running much too cool. Restrict cooling water flow and get operating temp higher. Running a diesel cold is death to engine.

Actually there are a lot of raw cooled diesels up here in the PNW and the damn things seem to last a long time. The logic evades me too.....

[Pete7]

Perhaps it will need a pump to assist moving the water around. Good article on this website:

Calorifier

Pete